Catheters having multiple lumens are well known. Multi-lumen catheters are known to have use in infusion, perfusion, hemodialysis and other procedures. Duallumen catheters used for hemodialysis, for example, provide one lumen for arterial (intake) flow of blood to be purified and one lumen for venous (return) flow of purified blood.
In most cases a multi-lumen catheters may be used as or in the same procedure as other catheter types. For example, a multi-lumen catheter may be suitable for use in PTCA procedures. In typical PTCA procedures, a guiding catheter is percutaneously introduced into the cardiovascular system of a patient through a vessel and advanced through therein until the distal end thereof is at a desired location in the vasculature. A guidewire and a dilatation catheter having a balloon on the distal end thereof are introduced through the guiding catheter with the guidewire sliding through the dilatation catheter. The guidewire is first advanced out of the guiding catheter into the patient's coronary vasculature and the dilatation catheter is advanced over the previously advanced guidewire until the dilatation balloon is properly positioned across the lesion. Once in position across the lesion, the flexible, expandable, preformed balloon is inflated to a predetermined size with a liquid or gas at relatively high pressures, to radially compress the arthrosclerotic plaque of the lesion against the inside of the artery wall and thereby dilate the lumen of the artery. The balloon is then deflated to a small profile so that the dilatation catheter may be withdrawn from the patient's vasculature and blood flow resumed through the dilated artery.
In the above example the balloon catheter may include a guide wire lumen and an inflation lumen, and may also include one or more additional lumens. In another example a multi-lumen catheter may be suitable for the deliver of implantable medical devices such as stents, grafts, stent-grafts and vena cava filters.
The various types of dual-lumen catheters may include a variety of cross-sectional configurations such as for example: two semi-circular lumens arranged in a side-by-side configuration and formed within a unitary tube which is internally divided by a planar septum; two circular lumens arranged in a side-by-side configuration and formed within a unitary tube separated by a septum; circular and crescent-shaped lumens (or circle-C) arranged in a side-by-side configuration and formed within a unitary tube which is divided internally by a curved septum or wall by attaching the exterior surface of an inner tube along its length to the interior surface of an outer tube; elliptically-shaped and circular lumens arranged in a side-by-side configuration and formed within a unitary tube divided by a curved septum; and circular and annular lumens arranged in a coaxial configuration wherein an inner tube is placed within an outer tube and the lumens are divided by the exterior surface of the inner tube.
Some examples of coaxial, dual-lumen catheters may be found in U.S. Pat. Nos. 4,493,696; 4,037,599 and 5,053,004. Some examples of catheters having a triple-lumen configuration are shown in U.S. Pat. Nos. 4,072,146; 5,221,255; 5,221,256; 5,167,623; 5,207,648; 5,718,876 and 5,879,499.
In many of the known multi-lumen catheter configurations, the lumens are formed by tubular members that extend from the proximal to the distal end of the catheter, or partially therebetween. In some cases the tubular members are engaged together. Where the tubular members are engaged, typically the engagement is at one or both ends of the tubular members and/or includes bonds at specific locations along the length of the catheter.
Known multi-lumen catheter assemblies may be formed according to a variety of different methods. For example tubular members of a catheter may be engaged together at desired location by methods such as by heat welding, chemical welding or bonding, adhesive welding, mechanical engagement, etc. However, known methods of engagement, such as conventional heat welding may inadvertently damage one or more of the tubular members as heat may be transmitted to areas of the tubular members that are adjacent to the intended engagement site. Where heat is applied directly to the outer tubular member, the heat may damage the outer surface of the outer member and/or detrimentally affect its structural and/or performance characteristics.
In addition to the above, many engagement methods and direct tube formation methods, such as extrusion of a multi-tubular assembly, may lead to a formation of excess material, referred to as “webbing”, within one or more of the lumens of the assembly. This presence of webbing or other undesired formations may contribute to a condition known as “back boning”. The clinical effect of back boning is that when an elongate shaft is torqued, the tubular member fails to display a one to one torque response and has the effect of building input which is then subsequently and suddenly released. Back boning is a phenomenon which may occur in an unbalanced tube and which may be exacerbated by the presence of webbing or other undesired formations.
Accordingly, there is a need in the art for a method of producing a multi-lumen tubular member, such as a catheter, that reduces the potential for damaging the components of the catheter when they are engaged together. Such a method preferably causes one or more regions of the tubular members to be engaged with a minimum of engaged area and which has the ability to affect engagement without leading to imbalance of the resulting catheter assembly.
All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
The invention in various embodiments is summarized below. Additional details of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
The abstract provided herewith is intended to comply with 37 CFR 1.72 and is not intended be used in determining the scope of the claimed invention.